Variable-speed control device



H. L'. TANNER VARIABLE SPEED, coNTRoL DEVICE i riledkuy 5, 192e 2 Sheets-Sheet 1 MM TORNEYS INVENTOR Eff/7er e a I BY Har/y Dec. 9, 1930.` H, L, TANNER 1,784,504

VARIABLE SPEED CONTROL DEVICE n Patented 9, 1930 clutches, servo-motors and the like.

Nr. oFFlcE HARRY L. TANNER, F BROOKLYN; NEW YORK, ASSIGN OR TO FORD INSTRUMENT C0111- PANY, INC., *OF LONG ISLAND CITY, NEW YORK, .A CORPORATION 0F NEW YORK VARIABLE-SPEED CONTROL 'DEVICE Application 1aed may 5,v 192s. lseminato. 106,917.

This invention relates to variable speed control devices and particularlyto devices for effecting the variable speed 'control of Heretofore, such.mechanisms as are commonly known as follow-up mechanlsms,

servo-motors` and the like, have been ineicontrolled according to the variable speed input motion.

The principal object of this invention is to provide a variable speed control mechanism which is smooth-acting, reliable and simple in operation, and effective and eiiicient for readily following andtransmitting variable speed motion, and for amplifying the power input thereof,..to any desired degree.

Another object of this invention is to provide a follow-up mechanism or servo-motor having relatively movable primary and secs. ondary elements, to a member of one of which is imparted a vibratory or oscillatory motion other than the relative movements between the elements, which vibratory 'motion with vextreme lrapidity intermittently effects the.

variable energization and consequently varying ressure of a power clutch to move the secondary element to follow the movements 'of the. primary element. The vibrating member thus controlsthe clutch, servo-motor, or

' the like, by rapidly varying the energization thereof proportionally to the movements of the primary element.- Inasmuch as the members controlling both forward and reverse directions of movement are energized by the vibratory make-and-break action but for varying lengths of time depending upon the l direction .of movement of the primary, the

secondary element is capable of instanta- T neous and minutely variable movement so that a smooth ositi've following motion of the secondary e ement results.

Other objects and advantages of this invention lwill become apparent from the following description of a preferred embodi- 'and an electro-magnetic-clutch actuated ac- `cordlng to such motion;

Fig. 3-a is supplementary? to Fig. 3, and shows a modification of the vibrator mechanism illustrated in Fig. 3;

Fig. 5 is a cross-section of the elect-romagnetic clutch of special design preferably utilized; l.

Fig., 6 is a view of a preferred embodiment of the invention as it may be associated with a gyroscope to transmit the movement thereof; and v i Fig'. 7-is an enlarged view of ameans for imparting vibrato'ry movement to one of the elements of the device.

AReferring particularly to Fig. 1, numeral 1 designates a Contact trolley or roller of conducting material and which is connected to I Aelement of 'the system, the movements of which are adapted to be followed by the secondary or following element, and which may be represented by commutator 4 cnsistin esstmtially of spaced contacts 5 and 6 mounte upon a block of insulatingmaterial. A' pair of-leads 7 and 8 are attached'to contacts 5 and 6, respectively, and to magnetic vibrator l coils 9 and 10, respectively, whereby a lateral reciprocatory or vibratory motion is imparted to member 4 as roller 1 engages either one of contacts 5 or 6 and thus alternately eneggizes magnet coils 9 and 10, respectively. his is more clearly yillustrated by Fig. 7 in which commutator 4 is shown to be pivotally,

ment of the invention las illustrated by the 5,5

60 'and 19, a shrtcircuit is established between "line k2 through resistance 27, lead 26, lever 23 andjeither contact 24,0r 25 coi-lf'20` or 21,;respectively. .E65

mounted at 11 and carries an armature 12 which is attracted to either magnet coil 9 or 10 according 'to whether roller 1 engages either one of contacts 5 or 6, respectively. It will be seen that when coil 9, for example, is energized by engagement of roller with contact 5, armature 12 will bedrawn oward coil9, thereby causing roller 1 to engage contact6 to energize coil 10. rlhis alternate energization of coils 9 and 10 is continuous whereby a vibratory motion is imparted to commutator 4, so that the resultant effect produced is a rapid relative movement between the respective contacts of the primary and secondary elements of the system. Centralizing springs 13 and 14 are attached to either side Aof com utator 4, as shown in Fig. 7, in order to alte the period of vibration thereof.

Connected across leads 7 and 8 and to side-2 of the electrical supply line by lead 15 are a pair of resistances` 16 and 17 which are l adapted to balance conductors 5 and 6, respectively, so that there will be no sparking as roller 1 moves between contacts 5 and 6. Resistances 5 and 6 have an additional utility which will be explained hereinafter.

Connected to vibrator coils 9 and 10y by means of leads 18'and 1 9 are the opposite coils 20a'nd 21,! respectively, of the electro-y magnetic clutch which is preferably of the type illustrated in Fig. 5. The terminals of clutch coils 20 and 21 are connected by lead 22 to the other side 3 of the electrical supply line. The clutch, being power driven, actuates the secondary element in accordance with the movements of the primary element, inasmuch as the clutch is intermittently energized so that it imparts a series of pressure impulses of a varying degree with extreme rapidity to the secondary element, which produce the effect of a constant and smooth following motion. .Moreoven such rapid energization and variable pressure of the clutch imparts great sensitivity to the mechanism and a correspending accuracy results. It is obvious that a servo-motor or like apparatus may be substitutedfor the clutch and controlled by the vibrating commutator in the same' manner.

If a hunting -tendency between the primary and secondary elements uof the system develops, contact lever 23, which moves with the primary element of the system, inasmuch as it is frictionally connected thereto, engages veither one of .contacts 24 or 25, which are mounted on the secondary element and are connected to leads 18 and 19, respectively. Inasmuch as contact lever 23 is connected to .side'2 of the electrical supply line by lead 26 l through resistance 27, which is equivalent to the resistance of the circuit above leads' 18 to either clutch Accordingly, if a secondary 'eleme p carrying commutator 4,

tends to hunt or overrun to either one side or the other, another circuit is established through the clutch coilon the same side to increase the clutching `effect or pressure, whereupon the secondary member is actuated to decrease the time of return of roller 1 back t0 its central position. Accordingly, mechanical damping is effected in the clutch and hunting is prevented aswell as overrunning, inasmuchas the reversal takes place 90 ont of phase with the movement of roller 1, that is, when roller 1 is halfway in its path to one side of its central position. Y

vResistances 16 and 17'are preferably so designed that clutch coils 20 `and 21 are never completely de-energized, but that there is a continual leakage through lead 15 and through resistances 16 and 17 when there is no relative movement between the primary and secondaryj elements, nor is one side of the clutch completely de-energized when the other side is energized and drawing the secondary element to follow the movements of theprim'aryelement. Thepurposebeing that any sudden energization or reversal in the energization from one side of the clutch to the other sideis immediately transmitted to the driven parts without the delay commonly occasioned by the inertia of the moving parts. Such alternating energization, however, isinsuiiicient to cause any appreciable frictional resistance or dragging in the clutch when it is driving the secondary element, since the virtually continuous'hunting of the clutch is too rapid for the immediate response of the secondary element, which accordingly alwaysmoves smoothly and positivel Referring now to F ig.'2, a modi ycation of the device shown in Fig. 1 is illustrated, the modification being in that-the roller 1 of Fig.

1 is replaced by an .oscillating contact lever 28 which is mechanically oscillated by rod 29 eccentrically mounted by one end to a constantly rotating disc 30,.instead of the electrical oscillation effected in Fig. 1, lever 28 being connected to one side 2 ofthe electrical supply line. Lever 28 periodically makes and breaks the circuit with stationary contacts 31 and 32 of the secondary element of the system and which are the 'equivalentsof contacts 5 and 6 of Fig. 1. The remainder of the circuit is like that of Fig. 1 with the exception of side of roller 1 and operate to magnetically .dampen the movements thereof. For example, if a hunting tendency between the primary and secondary elements of the system develops, lever 23 will make contact with either contact 24 or 25, whereby either coil 33 or 34-is respectively energized to draw..

, contacts 5 and 6 to which they are shown connected in Fig. 3, and are directly connected to supply lines 2 and 3, a rotatingv commutator switch 71 being inserted in line 2. Commutator switch 71 consists of a disc having an insulated sector and its edge is engaged by a pair of brushes 72 and 73 which are con-V nected to vibrator coils 9 and 10,.respectively,

whereby the latter are intermittently alternately energized as commutator 71 is revolved. The axis of commutator 71 is connected to line 2 by means of brush 74, and it may be rotated by the clutch driving means,

if desired.

Fig. 4 illustrates another modification of the device shown in Fig. 1 wherein theresistance of vibrator coils 9 and 10 is utilized for preventing sparking between roller 1 and contacts 5 and 6, and in connection with the ydamper for the same purpose as 'and thus eliminating resistances 16 and 17. Windings 35 and 36 are preferably provided in coils 9 andI 10, respectively, in order to furtherreduce the sparking, all other elements being identical with those shown in Fig. 1.y

Fig. 6 illustrates a manner in which the system of this invention may be adapted to follow and transmitl the movements or movement tendencies' of a gyroscope without exertingany load thereon, so that it is free to exert its natural tehdencies as e'ected by eX- traneous forces. lMoreover, such movements are followed and are supplied with a greater power from an auxiliary source, so that the movements of the'gyroscope or other like member may be utilized to indirectly effect the movements of large masses and exert large forces. The gyroscope 37 is suspended in a gimbal ring or rings in the usual manner, the outer ring being trunnioned in rigid standards 38 and 39for example One of the trunnions of the gyroscope carries an integial resilient crank arm 40, the end of which is bifurcated and carries the contact roller 1 which is connected to one side 2 of an electrical supply line and insulated from the remainder of arm 40i as shown. Thus the primary or followed element in this instance comprises the gyroscope 37, arm 40 and contact roller 1.

The secondaryor'following element Iof the system may be journalled in the rigid standard 41, and the shaft 42 thereof carries integral crank arm 43 upon which are mounted the vibrator magnets 9 and 10, assuming that the circuit and the `arrangement of Fig. 1 is preferred. Crank arm 43 is provided with an integral parallel extension 11 which pivotally carries vibratory commutator 4, to which contact roller 1 may move relatively in the manner heretofore described. Contact lever 23 of the damping means is frictionally mounted upon the hub of crank arm-4() by means of a spring washer or the like, as shown, so that when the following element tends to hunt with respect to the movements of the gyroscope 37, lever 23 makes contact with either contact 24 or 25, since it can slip relatively4 to the movement of crank arm 40 upon which it is mounted, whereby a circuit is established to stop thel hunting in the manner heretofore described.

The move-ment of roller 1 from its mid-v position as shown in Figs. 1, 3, 4 and 7 to engage either contact 5 or 6, accordingly energizes the vibrator coils and the electro-inagnetic clutch coils 20 or 21 which are mounted in a clutch ring 45 splined upon and adapted to continually rotatewith shaft 44, -which is driven by'an electric motor 46, or other power source, through bevel gears 47 and 48. A

pair lof bevel gears 49 and 50 are freely mounted upon shaft 44 and mesh with a bevel gear 51 attached toshaft 42 of the'sccondary or following elelnent of the system. Contact 5 is connected through lead 7, vibrator through either one of contacts 5 or 6, respectively, the central clutch ring/45 grips either gear 49 lor 50, respectively, and thereby drives the same, which motion is transmitted to shaft 42 and arm 43 to move commutator 4 bodily in the same direction that roller 1 has been moved. This motion is smooth and continuously follows the movements of the primary elements since the variable pressure in the clutch effects the movement as it is en ergized by the movement of the primary element. The follow-up movement of the secondary element ofthe system may be utilized l0 clutch ring 45nis to drive other means in synchronism with the movement of the gyroscope 37 by mounting a gear 55 upon shaft 42 which drives another gear 56 attached to an output shaft 57.

In order that the movement tendency of the gyroscope may be followed simultoneously and without hesitation, a specially designed electro-magnetic clutch is preferable, and may be .of the type shown in Fig. 5 The :eyed to power driven shaft 44' so that it rotates therewith and is axially immovable. Clutch ring 45 is provided with magnetic coils 2O and 21 to which, v'through slip rings, are connected their respective brushes 18 and 19 and the common lbrush 22.

Clutch ring 45 alsocairies a pair of friction rings 58 and 59 which Vare always in close proximity to friction discs 60 and 61 which are securely attached Vto gears 49and 50, re-

spectively. Gears 49 and 50 are freely rotatable on balljbea'rings, the respective inner races of 62 and 63 of which are securely attached to shaft 44 in the usuahmanner of mounting ball bearings. A slight axial-motion between the gear unitsv 49and 50 'and shaft 44 is provided for which is sutlicient to allow gears 49 and 50 and their respective friction discs 60 and 61 to be drawn into frictional engagement with friction rings 58 and 59, respectively, as the electro-magnetic coils of the clutcl are energized. A number of axially disposed pins 64 are slidably mounted in clutch` ring through friction discs 60 and 61, and their ends are embedded in or bear against the linner ball races ,62 and 63 so that they have axial play.' Accordingly,A

one disc is pushed away from its friction ring when the opposite disc is drawn to its friction ring due to the energization of one of the magnet coils, thus effecting a rapid clutching alternation from one side to another, or forward to reverse and vice versa. and reverse drive ofv shaft 42 is effected through bevel gear 51 meshing with diametricallyopposite bevel gears and 66, which are integrally mounted with spur gears 67 and 68, respectively, upon a j ack-shaft 7 0, so

that spur gears 67 and 68 mesh` with and are driven by gears 49 and 50, respectively, when In the manner hereinbefore described, each 4of the electro-magnetic coils is always at least slightly energized due to leakage in the electrical circuit, but such energization is` not sufficient to offer resistance or dragging to the rotating clutch ring 45, but is intended to maintain each one of friction discs 60 and l61 in intimate proximity to their respective friction rings 58 and 59, so that there may be no delay between the time of energizationV ,f and clutching, andthus a smooth motion of the follower is .obtained sinceJ 'the pressure l of the clutch varies as the degree of energization. For the same reason the masses of' The forward lead 19, clutch coil 21 and lead 22 to thel other side-3 of electrical supply line, but the vibrator will continuously operate to control the clutch as long as the movement 'of the gyroscope continues. The energization of clutch coil 21, probably augmented an instant later by the circuit established between lever 23 and contact 25 dueto the overrunning tendency of the sudden reversal, clutches' disc 61 to friction ring. 59, and the direction of rotation of shaft 42 is reversed through gears 50, 68, 66 and 51. Inasmuch as motor 46 is driving clutch ring 45 at constant speed', and as the speed of the primary element usually varies periodically, there isneces- .sarily some slippage between clutch ring 45 and friction discs 60 and 61 so that the actual primary input speed may be reproduced accurately. It is obvious that a larger motor or power source maybe utilized whereby a greater power and a larger torque may be supplied to the following motion.

' While `only one step in the operation of the system in both directions has been described in detail, yit is evident that the successive steps are instantaneous and continuous as the primary element moves, and also that, while a preferred embodiment of this invention has been illustrated and described, it is to be understood that modifications in design and detail maybe freely made and spirit-of this invention` within the scope of the appended claims.

I claim tion of abodily movable contact having vibratory movement distinct from its bodily the latter are clutched to rotating clutch ring one of them tol` follow the movement of the other.

2. In a follow-up mechanism, the combination of relatively movable primary and 1. In a follow-up mechanism the combina-v actuated by one of said contacts for causing secondary elements, normally engaging contacts associated with said elements,.means for vibrating one of said contacts relatively to said elements, and means controlled by said vibrating means for moving said secondary element in accordance with the movements of said primary element.

3. In a follow-up 1nechanism,the combi- 50.- ondary elements, normally engaging contacts nation vwith relatively movable followed and following element-s, of a contact associated with one of said elements and vibratory with respect to said element, a normally relative- ,lyy stationary contact associated with said other element and engaging said first named contact, means controlled by said Vfollowed element for'vibrating said first-named contact,` and means controlledby said vfirstnamed contact for moving said' following element only in accordance with the movements of said followed element.

4. In a variable speed-control device, a" pair of relativelyand bodily movable contacts, means for moving one of said contacts,

means energized by said 'movement for vibrating said other contact, and power means actuated by said vibrating contact for moving the same to follow the movements of said moving contact.

5. In a variable speed control device, the combination of a Apair of relatively movable engaging contacts, means for vibrating one of said contacts actuated by relative movement between saidL contacts, and means controlled by said vibrating contact for maintaining said vcontacts in juxtapositionirrespective of their several bodily movements.

6. In a variable'speed control device, the -combination of. an electromagnetic power member, and means for controlling said member, said means lcomprising relatively'movable contacts, means actuated by relative movement between said contacts for vibrating one of said contacts, and means whereby the vibrating contact energizes said member to follow the bodily' movement of one of said member in accordance with the movement of said followed member. i

8. In mechanism of the character Ide` scribed, relatively movable primary and secassociated with each of said elements, means controlled by the movement1 of said primary element relatively to said secondary element for oscillating one of said contacts, and'means controlled by said oscillating contact for moving said secondary element to follow said primary element.

bination of a primary element, a. secondary element associated therewith, means' for vibrating one of said elements, said means ac,-

tuated by relative movement between said elements, and mechanism energized'by the lv1- element to fellow the movements of the pri- 'mary element.

10. In a servo-motor mechanisxmthe combination of a primary element, an electrical Contact associated therewith, a secondary ele-` ment, a commutator associated therewith and engaging said contact, means for vibrating said commutatr upon relative movement between said contact and said commutatorand an electromagnetic clutch energized by vthe vibrations .of said commutator for moving said secondary element to follow said primary element. y 1,1. In a servo-,motor mechanism, the combination of a followed memberfa vibrating follower member associated therewith, a sup,

port for said follower, means energized by relative movement between said members to vibrate said follower for continuously making and breaking an electrical circuit between them, an electromagnetic clutch and means wherebysaid clutch maintains said support substantially fixed with respect to said followed member according to the circuit make and break between said members.

12. In a servo-motor mechanism, the'combination of primary and secondary elements, a contact associated with the primary element, a commutator engaging said Contact and associated with the secondary element, means for making and breaking the electrical circuit between said contact and commutator, said meansbeing energized by relative motion between them, an electro-magnetic clutch intermittently energized by the make and break of'fthe circuit, and means actuated by said"clutch for maintaining the secondary element substantially fixed with respect to the primary element.

13. In a clutch control mechanism, the combination of primary and secondary elements subject to hunting, a clutch for driving said secondary element, means to control said clutch, and an auxiliary control mechanism for vsaid clutch actuable to prevent huntin 1 14. n a variable speed control mecha-.

nism, the combination of relatively movable elements subject to excessive oscillation, mechanism for causing one element to follow'the movement of the other element, and an auxiliary controlling device actuated by excessive relative movement between said mechanism to A,dampen the;f oscillations.

f 15. In a variable speed control mechanism,-

the combination of relatively movable .ele-

` v ments subject to hunting, mechanism con- 9. Ina servo-motor mechanism, the comtrolled by. the relative movement between said elements for keeping them in )uxtaposition, and an auxiliary controlling de-vice operated by the movement of said elements for actuating said mechanism rto prevent the hunting.

65 bratingelement for causing the secondary 16. In a variable speed' control ,device having primary and secondary elements subject to hunting, mechanism actuated by the movement between said elements for driving said secondary element, and an auxiliary controlling device actuated by the movement between the elements for controlling said mechanism to prevent the hunting.

17. In a follow-up mechanism, the combi nation with relatively movable followed and following elements, ofa relatively Vibrated Contact associated with one of said elements,

a normally relatively stationary contact associated with said other element and engaging said first-named contact, means for vibrating said irst-namedfcontact, and means controlled by said first-named contact for moving said following element in accordance with the movements of said followed element.

18. In a follow-up mechanism, a pair of relatively ixed contacts, a Single contact co5Y operating electrically therewith, means for causing continuous oscillatory relative displacement between the-pair of contacts and the single contact, a controlling. element, means controlled thereby for relatively displacing the pair of contacts and the single cont-act, a follow-up power element, means controlled by the contacts for operating the power element to restore the pair of contacts and the single contact to their normal relation.

In testimony whereof I affix my signature.

HARRY L. TANNER. 

